Aircraft



.1. W. DYER lrs1-A1. 2,333,365

Nov. 2, 1943.

AIRCRAFT Filed July 26, 1935. e sheets-sheet 1 S/ 3 (A lloznC/q NOV. 2,1943. 1 W DYER ET AL 2,333,365

AIRCRAFT Filed July 26, 1935 6 SheetS-Sheet 2 Nov. 2, 1943. J. w. DYERET A1.

AIRCRAFT Filed July 26, 1935 6 Sheets-Shee 5 VENTO/QS uw bb Nov. 2,1943. L W` DYER ET AL 2,333,365

AIRCRAFT Filed July 26, 1935 6 Sheets-Sheet 4 4 /A/ ,5A/roes yf/g' 5y@Arrow/fr Nov. 2, 1943. 1 w DYER ET A1.

AIRCRAFT Filed July 26, 1935 6 Sheets-Sheet 5 v'Patented Nov. 2, 1943UNITED STATI-:s PATENT orales'.

ARCRAFT John William Dyer and David Kay, Edinburgh,

Scotland, assigner-s to Kay Gyroplanes Limited, Edinburgh, ScotlandApplication my 2s, 1935, serai No. sassi 1n Great afnam July zr, 1934 13Claims. '('CL 244-18) (e. g., before taking off) and it is with therotor drive employed for this purpose that the present invention is moreparticularly concerned.

The usual method of driving the rotor initially prior to night is tocouple a power take-off shaft to the power unit of the aircraft by aclutch under the control of the pilot, said shaft being flexible orjointed and being provided with a starter pinion meshing with a suitablegear, such as a toothed annulus, associated with the rotor hub.

One object of the present invention is to provide an improved mountingfor supporting the said starter pinion in mesh with the gear associatedwith the rotor hub, another obtiect being to provide improved means forengaging and disengaging the pinion 'and also, if desired, forsimultaneously coupling and uncoupling the starter pinion and a powerunit.

With the above and other objects in View, in an aircraft of the kindreferred to, we provide mechanism for operatively connecting a powerunit and the rotor so that the latter shall be 1y under the action ofmeans which are operated by mechanism adapted to vary the angles ofincidence of the rotor blades. This is an important feature of thisinvention.

The pinion is also preferably so disposed and movable relatively to thegear wheel that the reaction of the teeth on the pinion and gear wheelwill cause the teeth to move into deeper rotated mechanically up to thespeed required prior to flight, said mechanism comprising a posedrelatively to a gear wheel associated with the rotor hub or otherrotor-supporting member that it can be swung into and out of mesh' withthe gear wheel.

The starter pinion is preferably connected to or integral with a spindlemounted on the rotorsub-supporting member in such a manner that the axisof the spindle can be moved in both directions along a curved pathtowards and away from a position in which it is engaged by a gear wheelassociated with the rotor hub, no matter whether the said supportingmember is in its normal position or inclined thereto or moved bodilytherefrom.

In an aircraft of the type referred to in which the angles of incidenceof the rotor blades are variable, it is preferable to arrange that thestarter pinion shall be disengaged from the gear wheel associated withthe rotor hub automaticalengagement when the pinion is driving the gearwheel, whereas if the gearwheel tends to drive thepinion the reactionbetween the teeth will tend to throw the pinion out of mesh with thegear wheel.

In one construction, the spindle is rotatably mounted in a housing whichis turnably arranged in a casing carried by the rotor-hub-supportingmember or mast. the longitudinal axis of the spindle being paralleltobutspaced or oifset from the longitudinal axis about which the saidhousing is adapted to turn in the casing, the starter pinion beingadapted to drive an internallytoothed member carried by the rotor hub.In

such a construction, the said housing' can be 4nein-,ed to the saidhousing by a cable, is adapted to turn the housing in both directions toengage and disengagel the starter pinion and its associated gear wheel,means being provided for holding the said control member in the positionin which the pinion and gear wheel are in engagement until such time asthe control member is released, either manually or automatically underthe action of control mechanism for varying the angles of incidence ofthe rotor'blades. Although one construction of the invention has beendescribed above as being applied to a rotor hub which is driven throughan internallytoothed annulus it will be understood that it could be madeto operate equally well in conjunction with an externally toothed gearwheel. It might be dimcult, however, to obtain such a compactarrangement in this case.` As applied to a rotor hub which is adapted tbe tilted laterally and longitudinally and, if' so desired, displacedbodily of the aircraft, a further feature of this invention consists inmounting the starter pinion supporting member on a part (such as therotor-carrying mast) whose inclination varies in accordance with theinclination of the rotor hub as a whole. In this connection, anarrangement for driving the rotor hub in accordance with the presentinvention may advantageously be combined with the rotor tiltingarrangement as described in our co-pending patent applications SerialNo. 33,395 and Serial No. 33,399, which have matured into Patents Nos.

2,097,117 and 2,097,118, in which the rotor huby is described as beingmounted on a form of mast provided at its `lower end with bracketmembers or side cheeks by which it is supported on a device forimparting lateral and permitting longitudinal swinging movement of therotor hub.

In applying the present invention to this arrangement, thepinion-supporting member is bolted or otherwise secured to the lowerpart of the mast or 'its supporting brackets or side cheeks.

In this way, the axis of rotation of the pinion will remain in itsproper position relative to the hub gear member no matter to what anglethe mast is inclined. It is necessary, however, in applying this featureof the invention, to provide a universal connection between the pinionspindle and its driving shaft in order to allow for the tilting andpossibly also to provide a telescopic connection at a suitable point toallow for the longitudinal tilting.

It will be seen that by employing a for the rotor hub constructed inaccordance with the present invention, a minimum of effort will berequired to move the driving pinion into or out of mesh since. in bothcases, the movement will be assisted by reaction set up between the twosets of meshing teeth.

One constructional embodiment of the invention applied to a rotor hubwill now be described, by way of example, with reference to theaccompanying drawings, whereon:

Fig. 1 is a side elevation of the front end of the aircraft of the typeabove referred to, but with the shell or skin of the aircraft beingshown in dotted lines in order that the detailed construction andarrangement of parts may be more clearly viewed and with the lifting orrotor blades broken for convenience of disclosure.

Fig. 1A is a view, partly in section, of the rotorsupporting mast withthe starter pinion and its associated gear wheel applied thereto;

Fig. 2 is a plan view, partly in section, on the line C-C,inFig. 1A;

Fig. 3 is a view showing the connection of the control cable to theturntable casing carrying the starter pinion;

Fig. 4 is a diagrammatic view showing the relative disposition on theaircraft of the control mechanism for the starter pinion and a clutchfor operatively coupling the engine tail shafttothestarter pinion;

Fig. 5 is a view, to a larger scale. of the control member for movingthe starter pinion into and out of engagement with the gear'wheelassociated with the rotor hub;

Fig. 6 is a view of the other side of the control member shown in Fig.5;

Fig. 'l is a view, also to a larger scale, showing the mechanism foractuating the clutch which operatively connects the starter pinion tothe tail shaft of the engine;

Fig. 8 is a sectional view taken substantially on line 8-9 of Fig. landshowing one type of dog-clutch which may be employed for connecting theengine with the engine tail shaft; and

final drive assaaos i Fig. 9 is a side elevation, with one of thesupporting plates removed, showing the holding means for the throw-of!clutch in the rotor blade drive.

n Referring to the drawings:

The method of mounting the rotor mast and the manner of tilting the sameis fully described in the specincations of our other co-pendingapplications, Serial Nos. 33,395 and 33,399.

Consequently, only a brief description will be necessary herein.

The rotor hub is turnably arranged upon the rotor-supporting mast ormember 2 which in turn has the laws l and 9A of its forked lower endpivotally mounted upon the bearing parts 4 and 9 of the crank pin memberor barrel 9 of the hinge-pin member or Z crank 1 (see Figs. 1A and 2).The latter also comprises the control shaft 9 which is turnable inbearings la in the rotor system supporting structure 9 and upon whichthe said member or barrel is nxed-` The axis of the shaft 9 is set atright angles to the longitudinal axis D-D` of the aircraft and,consequently, the axis of the Amember or barrel 6 is inclined at anangle thereto. Cheek plates Ill and Illa are secured respectively to thejaws 9 and 3A and are interconnected at their rear ends by a cross pinto which is connected one end of a link l2 that anchors the rear end ofthe rotor support adjustably to the structure 9. This adjustableanchorage may be accomplished by connecting the lower end of the linkvI2 for universal movement to a threaded spindle |2a engaging in acorrespondingly threaded bore |2b of a cable drum or pulley I2c,rotatably mounted in a bearing I2d to the rotor supporting structure 9.The drumor pulley |2c is provided with grooves 12e for the reception ofthe operating cable |21, Fig. 1, which passes over the Ahand wheel Fpreferably disposed in the cockpit P. y

The lateral tilting of the mast and rotor on the supporting structure 9is accomplished by the wheel L disposed in the cockpit adjacent thepilots seat and mounted ona shaft 8|. This shaft 9| has a cable pulley92 over which passes the cable 83 which cooperatively engage a cabledrum 9b, Fig. 2, which through mechanism disclosed in detail in ourco-pending application Serial No..33,395 rotates the shaft 8 and,consequently, the Z barrel 6, 'which' is keyed thereto, causing relativemovement between the Z crank 1 and the jaws and 3A which support themast thus effecting a lateral tilting of the mast l and the rotorsupported thereby according to the direction of rotation of the shaft 8.

Rotation of the shaft 8 by the hand wheel L will cause the Z crank 1 totilt the rotor mast 2 to either side according to the direction ofrotation, and, since the link |2 will bias such movement, causes themast to incline forwardly or rearwardly as the case may be, as well asto tilt laterally, as explained in our copending application Serial No.33,395. The partly lateral and partly fore and aft movement of the mast,therefore, is forward on one side and rearward on the other of a planeat right angles to an axis Z-Z and passing through the axis of the mast2. The fore and aft setting of the mast 2 may be varied by rotating thedrum |2c by the hand wheel F which will raise or lower the point ofanchorage of the end of the mast base or carriage provided by the parts3, 3a, I0, and lila.

The rotor hub concentrically surrounds the mast 2 and is mounted thereonby antifrictional bearings 84 and 89 in any suitable manner.

autogyro type. These link blocks 89 are free to pivot on the barrels 88to permit substantial vertical flapping movement of the blades when theblades are revolving about the mast 2, but each is prevented fromdropping too far when the blades are stationary or only slowly rotating,by meansof stops 90 adapted to cooperate with shoulders 9| on the flangedisc 29 secured by bolts 92 to the rotor hub I. (Figs. 1 and 1A.)

The spar 93a (see Figs. 1 and 1A) of each rotor blade is pivotallyconnected to the link-block 89 for lateral movement ,on the generalplane of rotation of the rotor-that is, about a substantially verticalpivot pin 94 provided in the linkblock 89 and passing through openingsin the jaws of the forked end of the spar 93a.

The angle of incidence of each of the rotor blades 93 is varied byturning, preferably simultaneously, the pins or axles 81 of the Z crankmembers 88 in the desired direction and to the desired degree. morespeciiically vdescribed and claimed in our co-pending' application`Serial No. 33,398. Briefly, the angles of incidence of the rotor bladesare varied by means which comprise a spindle 95 disposed within thehollow mast 2 and having a threaded end 95a in threaded engagement witha complementally threaded portion of the mast through the upper end ofwhich the spindle extends, as at 95h. The lower end portion of thespindle is provided with a longitudinal bore 95e therein, in whichslidably extends a shaft 96, splined therewith at 96a, forming atelescopic joint. The lower end of the shaft 96 is connected to theupper end of a drum spindle 91 by means of a link 98 and universaljoints 99, the spindle 91 being journalled in the bottom wall of thehousing structure 9 through which it extends downwardly and having fastthereon a cable drum |00. Thus, irrespective of what may be theinclination and/or body displacement of the rotor mast 2 within thelimits allowed by the mechanism, the telescopic joint formed by theparts 95e and 96 and the universal joints 99 will allow the spindle 95to be rotated by the drum |00 and, by virtue of the coacting threads95a, will be reciprocated longitudinally of the mast:

Mounted on the top of the rotor hub I and fast thereto-is a hubextension |0| from which extends radial arms |02, there being as many ofthese arms as there are rotor blades 93, and each being pivotedintermediate their length, at |03. A collar |04 surrounds andyisrotatably mounted upon the upward extended end of the spindle 95h andhas horizontal portions |05 which engage forked end portions |06 on theinner ends of the arms |02.

'Each of the pins or axles 81 of the Z-cranks 88 have fixed to one endthereof a lever |01, the

outer end of which is connected to the outer end of an adjacent arm |02by an adjustable link |08. Also, fast on each of the pins or axles 81 isan ear I 09 to which one end of the tension spring ||0 is connected, theopposite end of the spring being connected to an anchor plate This isaccomplished by means secured to the hub I, the ears |09 each having astop |I2 normally engageable with an adjacent lligu II3 on the rotor hubby the tension spring 'I'he cable drum |00 is rotated by the cable I|4wound therearound and has its reaches led down legs III and II5', of therotor mast supporting pylon structure, into the cockpit (see Fig. l)from which they are led in opposite directions to the grooved surface ofa quadrant ||8 fixed on a rotatable spindle ||1 joumalled in bearingscarried by the supporting structure of the fuselage, the said spindleand quadrant being os cillatable through the medium of the control leverI I8.

As shown in Fig. 1, the lever ||8 may be moved to positions for varyingthe angle of incidence of each of the rotor blades by properlypositioning the lever with respect to a stationary quadrant II9. Thelever ||8 may be located in the running up or no-lift position bypositioning it at the forward or left hand end of the quadrant II9, asviewed in Fig. 1, and may be located in maximum angle of incidence orlifting position by moving it to the rear or right handle end of thestationary quadrant II9, as viewed in Fig. 1. For normal flightpositions, at any desired angle .of incidence, the lever may assumevarious positions intermediate the ends of the quadrant ||9, movement ofthe lever ||8 in either direction transmitting a corresponding movementto the cable I4 which will correspondingly operate the drum |00 and thespindle 95.

Movement of the lever ||8 is also transmitted to a short arm lever I |8athrough a link l 20, Figs. 1 and 6, to the lever 54 fixed to the shaft54a of the pointer |23 a blade of incidence indicator |24. Attached tothe pointer |23 or its shaft 54a is a lever arm I 25 to which isattached one end of a tie-bar |3| for the purposes of releasing themanually operablemclutch 11 to disconnect the motor 16 or other sourceof power from the rotor hub I, when the angle of incidence of the rotorblades has been increased a predetermined amount, as more fullydescribed in our copending application Serial No. 33,396 and thereforeonly briefly referred to here with reference to Fig. 9.

With reference to Figs. 1 and 9, the manually operated frictional clutch11 is biased by a spring means which will normally urge the clutch tode-clutched position and may be operated to clutched position by anysuitable linkage or leverage, indicated by the numeral |26, connected`"with an operating handle |21 in the cockpit disposed within the reachof the pilot. The handle |21 is pivoted between supporting plates |28and is provided on one end with a ratchet tooth segment |29 so arrangedas to be engaged when required by pawl |30 loosely carried on a pivotpin |32 engaging an elongated slot |33 in the pawl.

When the clutch 11 is disengaged or in declutched position its operatinglever |21, ratchet |29, and pawl |30 are in the positions shown in fulllines Figs. 1 and 9. A spring 32 tends to hold the pawl in thisposition. A slidable lockbar |35 is disposed between the plates |28 andis free to slide from the position shown in full lines .of Fig. 9 intothe position shown in dotted lines or vice versa. The lock-bar |35 .hasa reduced lower end forming a shoulder |38. When the slide bar is infull line position shown, a corner |31 of the pawl lies opposite andjust clears or only lightly ytouches the unreduced portion of the barwhich forms an abutment or obstruction to pivotal movement of the pawlaway from cooperative relation with the ratchet teeth |23.

To eilect an engagement or clutching of the clutch 11, the handle I21 israised, which causes the ratchet teeth |28 to engage the pawl |30against the resistance of the spring I 34, and, by virtue of the shapeand disposition of the slot |33 in the pawl, the resultant movement ofthe pawl is virtually a rotation about its corner |31 in a clockwisedirection. Thus, the clutch 11 will be engaged and the pawl will retainthe operating handle |21 in position to maintain this clutchingengagement.

With the clutch operating lever |21 in the above mentioned position andwhen the angles of incidence of the rotor blades 83 have been increasedto a predetermined extent by movement of the lever |I8 in the mannerabove described, the rod I3I will move the lock-bar I35 to a positionindicated in dotted lines Fig. 9 and theV reduced portion of thelock-bar will lie opposite the corner |31 of the pawl, whereby thepawlmay then turn in a counterclockwise direction about the pin |32, underthe influence of the pressure exerted on the other side of the pawl bythe ratchet |29. clear of cooperative engagement with the ratchet teeth|29 and the clutch operating lever |21 will drop to its normal position,shown in full lines, and the clutch 11 will be disengaged.

The present invention is concerned more particularly with the mechanismabove described or its equivalent, or such portions thereof, as operatein combination with the starter pinion I8 and its operating parts now tobe more fully described. This starter pinion structure comprises ahollow outer casing I3 fixed by bolts I4 and I5 between the front endsof the jaws 3 and 3a, a hollow inner housing I6 carrying the starterpinion I8 and turnably arranged within the casing I3 with thelongitudinal axis A-A of the starter pinion I8 offset relatively to thelongitudinal axis B--B of the outer casing (Figs. 1A and 2).

Thus, the pawl will swing The spindle I1 of the starter pinion I8 isrotatably arranged in upper andlower needle rollerbearings I3 and 20,which are arranged in recesses 2| and 22 formed in the inner housing I6,the axes of said bearings and, consequently, that of the pinion I8 beingcoincident with the axis A-A of the bore of the inner housing and,therefore, offset from the axis B-B of the outer casing I3. A distancetube 23 surrounds the spindle I1 and extends between the two bearings I3and 20. A bearing-retaining plate 24 is fixed to the inner housing I6and is provided at the exterior of the casing I3 with a headed lockingpin 25 having a hole 26 for the passage of a cable therethrough, saidpin being secured in position by the nut 21.

From the above description it will be followed that the inner housing I6can be turned in the fixed outer casing I3 into and out of the positionin which the pinion I8 is respectively engaged with and disengaged fromthe internal teeth of a. crown Wheel 28 which is bolted to the bottomange 29 of the rotor hub I, the latter being turnably mounted on therotor mast 2 in the manner above described. There are, of course, manyways in which the inner housing I6 can be turned and one of them will bedescribed hereinafter. In the meantime, it may be noted that theposition of the cable locking pin 25, when the pinion is engaged withthe rotor gear 28, is shown by the line Y-B in Fig. 2, and, when thepinion is tripped out of engagement with the gear 28, by the line X-B.The lower end of the spindle I1 is fixed to a fork 38 and is connectedby a unlversal joint to the forked upper end of the telescopic rotordrive shaft 12 the lower end of which is connected by a universal joint13 to the power output shaft ofa gear-box 14 which may beV connected toan ouput tail shaft 15 from the engine 16 under the control of amanually operable friction clutch 11, see Fig. 1.

A cable 3|, Figs. 1, 3 and 4, is fixed to the plate 24 on the innerhousing I6 by means ofthe cable locking pin 25, the two ends of thecable being led r.t0 and passed in opposite directions around a contro1drum 32, Figs. 4 to 6, and fastened thereto by any suitable means suchas indicated at 32a, the control drum 132 having a handle 33 arrangednear to the pilot in the cockpit P, Fig. 1. The control drum 32 is urgedin such a. direction (as indicated by dotted lines in Fig. 5) by aninternal spring 32h that the pinion I8 will normally be held disengagedfrom the teeth of the crown wheel 28 but the drum is held in theposition, as shown in full linesin Fig. 5,. in which the pinion andcrown wheel are in mesh by the following arrangement: A spring-pressedpawl 34, Fig. 6, a manually operable trip 35 and a further trip 36A areal1 fixed to a turnable pivot pin 50, the pawl being adapted to'engagebehind an abutment 34A on the control 32 when the control has been movedin its full line position in which the pinion I8 is engaged with thewheel 28. A slide 36 is slidably mounted on the spindle 5I of thecontrol drum 32 and also on a pin 52 which is arranged in a bracketwhich supports the pawl and the trips 34 and 36A, The slide 36 isconnected by a pair of links 53 to a lever 54 arranged to be pivoted bythe control lever II8 through the medium of the link I3I, which leverII8 controls the angles of incidence of the rotor blades, Fig. 1, asdescribed and as more fully described and shown in our copendingapplication Serial No. 33,398. Thus, the pawl 34 can be tripped eitherby the trip 35 or by the slide 38 which, when the lever 54 is in theposition T--T has acted to depress the pawl 34 by the engagement of ashoulder or cam'element 55 with the trip 36A. The arrangement in thisconstruction is such that the pawl 34 is tripped through the slide 36when the incidence control mechanism has brought the rotor blades to thesaid incidence at which the above mentioned manually operated clutch 11is tripped. After the pawl 34 has been disengaged, the spring 32h (Fig.5) wi11 move the drum 32 to its dotted line position and therebyoperating the cable 3| to rotate the casing I6 from the position Y-B inwhich the pinion is engaged with the crown wheelinto the disengagedposition X-B. x

Obviously, arrangements must be made for the pinion I8 to be operativelyconnected to the Y engine 16 when the pinion is engaged with the crownwheel 28. In the present construction, this is arrived at Vby connectingone end of a cable 31 to the-drum 32 (Figs. 1, 4, 5 and 7), the cablebeing wound on the latter in a direction to insure that as the pinion I8is engaged with the crown wheel, simultaneously the engine will beoperatively connected to a shaftl in the rotor drive mechanism. In thisparticular construction, one element 18 of a dog-clutch (see Fig. 8) isslidably arranged on the engine crank shaft 19 and the other element 8IIon adjacent end of the power take-off or tail shaft 15, which is adaptedto drive the said pinion `I8 through mechanism including the throw-offclutch 11, gear-box 14, and the rotor drive shaft 12. The element 18 ofthe safety dog-clutch is operated by levers u and m on a rotatableeinen. un.

' or any other suitable means, connected by a rod is disengaged, ishooked to the lever 48, the other end of said spring being anchored to.the engine casing. The other arm of the bell crank lever 48 isprovidedwith a guide 4I through which passes a rod 42 upon which a coil spring43 is arranged, the opposite end of the spring abutting against a washerv44 backed by the lock-nuts 45. The end of the cable 31 is connected tothe rod 42 and, therefore, when the cable 31 is wound upon the drum 32,(as when the drum is in the full line position Fig. 5) the spring 43will be compressed between the guide l4I and washer 44 until such timeas the energy thus stored in the spring 43 will be sufficient te causethe bell-crank lever 40 to turn against the pull of the spring 48 and,through the rod 48 and lever 38, to engage the dog-clutch. It will beappreciated that the pawl 34, by retaining the drum 32 against movement,also acts to prevent the dog-clutch being disengaged under the influenceof the springs 43 and 46.

Limitation of the movement of the pinion I8 in the engaging direction isprovided for by the engagement of the edges 6B and 8| of flanges 62 and63 (Fig. 2) on the inner housing I8 with the edges 84 and 85 onbattlements 88 and 81 provided on the outer casing I3. Similarly,movement of the pinion in the disengaging direction is provided for bythe engagement of the edges 68 and 89 on the anges 62 and 83 with theedges 'I0 and 1I on the said battlements.

The eccentricity of the axis of rotation of the pinion I8 is such thatwhen the pinion is driving the crown wheel 28, the reaction between theengaging teeth will tend to force the teeth into deeper engagement.Conversely, in the event of the rotor hub overrunning the pinion thetendency will then be for the teeth on the pinion to be disengaged fromthose of the crown wheel and this will actually happen after the pawlbeen disengagedfrom the drum 32. i

Although reference has been made above to a toothed starter pinion andthe associated toothed gear wheel, it might be possible to use afriction pinion and wheel in some machines. In the operation of theaircraft above described, the rotor blades are normally kept at negativeangle of incidence when on the ground. Before taking off, the pilotoperates the handle 33 to the full line position shown in Fig. 5 toengage the dogclutch 18-80 and to engage the starter pinion I8 with thegear 28, it being understood, of course, that the throw-off clutch 11 isin de-clutched position and its operating lever I21 is in the full 34has .es the lever n3 is Amoved to the maximuml angle of incidenceposition, it operates link |20,l Y, lever 34, link I3, slide", pawl 38A,which consequently releases the pawl 34 fromv engagement with theshoulder or -tnoth 34A on the drum`32A (seeFigs. 1, 6, and 9). Thisbeing accomplished,

the spring 32h moves the drum 32 and itshan-` die 33 to the dotted uneposition shown in Fig. 5 whichy actuate, through the cable 3|, andhousing I8, to disengage the pinion I8 from the gear 28; and at the sametime the drum 32 slackens the cable 31, allowing the dog-clutch18-80 tobe disengaged through the medium of the rod 33, lever arms 38 and 38a.which are actuated by the springs 43 and 48. Also while this is takingplace, movement of the lever I4 moves spindle 54a of the angle oi'incidence indicator I24 which, through the rod I3I moves the lock barI35 to its dotted line position (Fig. 9), allowing the pawl |30 todisengage the throw-oi! clutch operating lever I21, which moves to its'normal disengaging position, lallowing the clutchr 11 to move tode-clutched position, hence cutting off all drive from the motor 'I8 orother source of power. Thus, vthe aircraft becomes air borne after aforward run, the length .of which' depends to some extent upon the speedobtained by the rotor I before the drive is disconnected. Theoretically,it should be possible to take oil* in still air with no forward run.When the machine has climbed to the desired altitude, the pilot movesthe rotor blade incidence control lever II8 forwardly or to the left inFig. 1 for a distance to adjust angularity of the rotor blades toaidesired or required normal flight position.

Having thus fully described the invention in one of its preferredembodiments, and the manner in which the same is to be performed, it isto be understood that the invention is not to be limited specifically tothe details of construction or to the organization of parts hereindescribed because the invention is susceptible of various changes andmodifications and is only to 4be limited to such arrangements as fallwithin the line position shown in Figs. 1 and 9. The eno gine is thenstarted, if not already running, andf mined speed has been reached, thebrakes of the aircraft (or other equivalent means) are releasd, and theincidence control lever II8 is pulled backward or to the right in Fig. 1to the maximum blade angle of incidence position, this beingaccomplished through the cable II4 rotating cable drum |00.

scope of the appended claims, having due regard for equivalents.

We claim:

1. In an aircraft of the kind referred to, a rotor having variableincidence blades, means for varying the incidence of said blades,driving means, mechanism for operatively connecting the driving means tothe rotor, said mechanism including a gear wheel associated with therotor and fa starter pinion mounted and disposed relatively to said gearwheel so that it can be moved into and out of mesh with the latter,means for locking said starter pinion into mesh with said gear wheel andmeans operated by operation of said incidence Varying means to releasesaid locking means.

2. In an aircraft of the kind referred to, a rotor having variableincidence blades, means for varying the incidence of said blades, adisconnectable power drive for said rotor; and means connected to saidincidence varying means, and operable in response to operation thereofto increase the pitch of the blades, for disconnecting said power drivefrom said rotor.

3. In an aircraft of the kind referred to, a rotor, driving means,mechanism for operatively connecting the driving means to the rotor,said mechanism including a gear wheel associated with the rotor and asingle starter pinion mounted and disposed relatively to said4 gearwheel for movement directly into and out of mesh with the latter, meansfor locking said starter pinion into mesh with said gear wheel, andmeans for releasing said locking means at will.

4. In an aircraft of the kind referred to, a rotor having variableincidence blades, means for varying theincidence of said blades, drivingmeans, mechanism for operatively connecting the driving means to therotor, said mechanism including a gear wheel associated with the rotorand a starter pinion mounted and disposed relatively to said gear wheelso that it can be moved into and out of mesh with the latter, means forlocking said starter pinion into mesh with said gear wheel, means forreleasing said locking means actuated manually and means connected tosaid incidence varying means and operable in response to operationthereof to release said locking means.

5. In an aircraft of the kind referred to, a rotor, driving means,mechanism for operatively connecting the driving means to the rotor,said mechanism including a gear wheel associated with the rotor and astarter pinion mountedand disposed relatively to said gear wheel so thatit can be moved into and out of mesh with the latter, means for lockingsaid starter pinion into mesh with said gear wheel, a clutch connectingsaid driving means with said starter pinion, and a single control meansconnected to both said locking means and said clutch for substantiallysimultaneously releasing said locking means and said clutch.

6. In an aircraft of the kind referred to, a rotor, driving means,mechanism for operatively connecting the driving means to the rotor,said mechanism including a gear wheel associated with the rotor and astarter pinion mounted and disposed relatively to said gear wheel sothat it can be moved into and out of mesh with the latter, means forlocking said starter pinion into mesh with said gear wheel, a clutchconnecting said driving means with said starter pinion, and manualcontrol means connected to both said locking means and said clutch forsubstantially l simultaneously releasing said locking means and saidclutch.

'7. In an aircraft of the kind referred to, a rotor having variableincidence blades, means for varying the incidence of said blades,driving means,

, mechanism for operatively connecting the driving means to the rotor,said mechanism including a gear wheel associated with the rotor and astarter pinion mounted and disposed relatively to said gear wheel sothat it can be moved into and out of mesh with the latter, means forlocking said starter pinion into mesh with said gear wheel, a

'clutch connecting said driving means with said starter pinion, a singlecontrol means connected to bothlsaid locking means and said clutch forsubstantially simultaneously releasing said locking means and saidclutch, manual operating means for said control means, and meansconnected to said incidence varying means and operable in response tooperation thereof to operate said single control means.

8. In an aircraft of the kind referred to, a rotor, driving means forsaid rotor, means for connecting and disconnecting said driving means toand from the rotor, biasing means tending to move said connecting anddisconnecting means intov disconnecting position, a trip arranged tohold said connecting and disconnecting means in connecting positionagainst the tension of said biasing means, manual means for moving saidconnecting and disconnecting means into connecting operation thereof tooperate said Single control means and said incidence varying means.

10. In an aircraft of the kind referred to, a rotor having variableincidence blades, means for varying the incidence of said blades,driving means for said rotor, means for connecting and disconnectingsaid driving means to and from the rotor, biasing means tending to movesaid connecting and disconnecting means into disconnecting position, atrip arranged to hold said connecting and disconnecting means inconnecting posi-l tion against the tension of said biasing means, acrank arm rotated in the operation of said incidence varying means, aslide bar having an elongated slot with relatively fixed spaced pinsextending in said slot for guiding said slide bar in straight linemovement, motion transmitting linkage connecting said slide bar withsaid crank arm for sliding movement in response to operation of saidincidence varying means, said slide bar being provided with a camelement arranged to operatively engage with the said trip to release itto allow the biasing means to operate.

.11. An aircraft, as claimed in claim 10, in which the trip element isprovided with means permitting manual operation thereof at will.

12. In an aircraft of the kind described, a rotor having variableincidence sustaining blades,-

means for varying the incidence of said blades, a power drive` for therotor and including a clutch means in said power drive, means connectedto said incidence varying means and said clutch means f or disconnectingthe power drive from lsaid rotor upon movement of the incidence varyingmeans from a negative angle of incidence to a positive angle ofincidence, and safety means normally biased to break the connectionbetween said power drive and the rotorl when the blades are in otherthan a negative no-lift angle of incidence, whereby the rotor will notbe rotated from the power drive should the clutch means be engaged whilethe blades are in a positive angle of incidence.

13. In an aircraft of the kind described a rotor having variableincidence sustaining blades, means for varying the angles of incidenceof the rotor blades, `mechanism for driving the rotor including aplurality ofdisconnectable means, and means operatively connected withsaid angle varying means and operable in response to movement thereof tooperate one of said disconnectable means to break the connection betweenthe.

rotor and its driving means automatically as soon as the blades havebeenadjusted or set to predetermined angles of incidence, one of saiddisconnectable means comprising a starter pinion adapted to be placedinto and out of mesh with a gear wheel on the rotor hub.

- JOHN WILLIAM DYER. DAVID KAY.

